From Refugio Elola walk up to Hoya de Antón following a signed path and go through this plain pointing to the left (South), towards Portilla Bermeja.
From Hoya's left final part and after a steep first section reach a rather little plain where the slopes of Portilla Bermeja and Portilla del Crampón join. Go up along the slope to the right (west), wich progressively is narrower and steeper (45º/50º). Once on Portilla del Crampón cross up the SW face (caution in winter) and climb the last meters directly to the right or to the left of some prominet rocks.
Update: after our June 2015 ascent we have figured that the first of the two II graded pitches on the last section has been modified, so now it is possible to climb up the embed rock just surrounding those to its right with no difficulty. Anyway, the second of the two more difficult pitches is still there neither having difficulty.
Portilla del Crampón is the most crowded route to Almanzor because of its less difficulty and short distance from Refugio Elola. In winter the upper part to Portilla (gap) del Crampón has a steep slope so it requires to take precautions. Crampons and ice axe are necessary from November to May. Also harness, a rope and some ice bolts could be indispensable.